<?php

/**
 * @package php-font-lib
 * @link    http://php-font-lib.googlecode.com/
 * @author  Fabien M�nager <fabien.menager@gmail.com>
 * @license http://www.gnu.org/copyleft/lesser.html GNU Lesser General Public License
 * @version $Id: font_table_hmtx.cls.php 40 2012-01-22 21:48:41Z fabien.menager $
 */

/**
 * `hmtx` font table.
 * 
 * @package php-font-lib
 */
class Font_Table_hmtx extends Font_Table {

    protected function _parse() {
        $font = $this->getFont();
        $offset = $font->pos();

        $numOfLongHorMetrics = $font->getData("hhea", "numOfLongHorMetrics");
        $numGlyphs = $font->getData("maxp", "numGlyphs");

        $font->seek($offset);

        $data = array();
        for ($gid = 0; $gid < $numOfLongHorMetrics; $gid++) {
            $advanceWidth = $font->readUInt16();
            $leftSideBearing = $font->readUInt16();
            $data[$gid] = array($advanceWidth, $leftSideBearing);
        }

        if ($numOfLongHorMetrics < $numGlyphs) {
            $lastWidth = end($data);
            $data = array_pad($data, $numGlyphs, $lastWidth);
        }

        $this->data = $data;
    }

    protected function _encode() {
        $font = $this->getFont();
        $subset = $font->getSubset();
        $data = $this->data;

        $length = 0;

        foreach ($subset as $gid) {
            $length += $font->writeUInt16($data[$gid][0]);
            $length += $font->writeUInt16($data[$gid][1]);
        }

        return $length;
    }

}